Acoustic analysis of parameters affecting the between-speaker variability in Persian-English bilinguals

Human voices are unique, and for this reason, speakers can be identified by their voices. This shows that speech sounds contain speaker-specific information that can be reflected in the acoustic properties of speech signals. There are many individuals around the world who speak two or more languages, adding a fascinating dimension of variability to language perception and production. However, it remains unclear whether bilinguals alter their voice when switching between languages. A holistic view of bilingualism suggests that bilinguals are an integrated whole that cannot be separated into distinct parts; instead, they possess their own specific linguistic configuration (Grosjean, 1989). Moreover, languages differ in their segment inventories, rules of segmental combinations, as well as spectral and rhythmic characteristics of speech. Speaking styles can also contribute to within-speaker variability in acoustic parameters. Despite these factors, little is known about the influence of language and speaking style on within- and between-speaker vocal variability. This study aims to investigate how acoustic features, specifically long-term F0 and long-term formant frequencies (F1-F4), contribute to speaker individuality in Persian-English bilingual speakers and to what extent these features can discriminate between bilingual speakers.